This invention relates to a suspension controller for a vehicle, and more particularly to a suspension controller which has the order of priority among various suspension controls.
In order to reduce shocks to a vehicle body depending upon the road condition and running condition of the vehicle, and furthermore to maintain control and high stability of the vehicle, various suspension controllers have been proposed. The suspension controller controls a suspension system, installed between a body and its wheels, by altering the spring constant, damping force, bush characteristic, stabilizer characteristic or the like. For example, the following suspension controllers have been provided: one which controls a suspension system by altering the spring constant of the air spring of the suspension system in response to the road condition (Japanese Published Unexamined Patent Application No. Sho-59-26638); one by altering both of the spring constant of the air spring and the damping force of the shock absorber (Japanese Published Unexamined Patent Application No. Sho-59-23712); one by altering the damping force of the shock absorber (Japanese Published Unexamined Patent Application No. Sho-58-30542); one by altering the bush characteristic or the stabilizer characteristic (Japanese Published Unexamined Patent Application No. Sho-58-26605 and Japanese Published Unexamined Utility Model Application No. Sho-59-129613).
The suspension control in response to the road condition is accomplished, for example, as follows. The suspension controller successively detects a distance between a wheel and the vehicle body as a vehicle height, compares a change of the vehicle height with a predetermined condition and, when the change satisfies the condition, alters the suspension characteristic so as to reduce a shock to the vehicle body. On the other hand, the suspension control in response to the running condition of the vehicle is accomplished, for example, as follows. The suspension controller detects a vehicle speed and a steering angle from sensors or detects a throttle valve opening or a brake action, compares each detected value with a predetermined condition and, when the value satisfies the condition, alters the suspension characteristic so as to stabilize the vehicle attitude.